Production of motor fuel



Patented Nov. 21,1944

rnonuc'rron OF MQTOR FUEL Albert Ernest Dunstan, London, and Stanley Francis Birch, Sunbury-on-Thames, England, assi'gnors, by mesne assignments, to Anglo- Iranian Oil Company Limited, London, England No Drawing. Application July 27; 1937, Serial No. 155,918. In Great Britain July 29, 1936 21 Claims.

This invention relates to the production of a high class motor fuel adapted for use as an aviation or motor spirit constituent of hi h antiknock rating and consisting essentially li' not entirely oi iso-paraillns.

According to the invention an oleflne is sub- Jected to contact with an iso-paraflin .(that is aparailln containing a tertiary carbon atom) in the presence oi a mineral acid, whereby on settlement an upper hydrocarbon layer separates which is composed-substantially oi saturated hydrocarbons boiling within the motor spirit range from of operation are advantageously such-that the liquid phase is maintained during the period of contact. Furthermore, the iso-paramn's may be employed in admixture with normal parafllns which are incapable of entering into the reaction. The oleflne too may be admixedwith inert' material. As a general rule, however, it is preterable to utilise both reactants in as pure'a state as possible, since there is a tendency for the yield to be poorer and dimculties may possibly be encountered in separating the non-reactive material from the product.

According to the invention moreover the isoparailin or iso-paraillns may advantageously be under the conditions hereinafter described'and' the products thereof. a

It is known to treat with sulphuric acid at low temperatures hydrocarbon fractions containing oletlnes that also contain iso-paraillnabutin such hydrocarbon fractions the content of the isoparaillns is low, and this-is the case in hydrocarbon fractions that contain lower oleflnes such as isoand normal butenes suitable for use ac- Y Where however equimolecular proportions oi iso-butane or iso-pentane and the selected olei'ines react (or equivalent proportions when the polymerides. or iso-butene are used) it is necessary that substantial amounts of theiso-paramns ln- (Cl. zoo-seat) dicated should be made available and advantageously also isolated, in' order that it may be possible for the saturated iso-paramn derivatives to be produced according to the invention on a practical or industrial scale and under conditions of practical convenience and economy. In carrying the invention into eflect an oleilne such as diisobutene is added to a mixture 0! an iso-paraflin such as isobutane inthe presence 01 amineral acid such as sulphuric acid (approximately 97 per cent) ,the mixture being thoroughly stirred. It is advisable that the oleflne should be added gradually to the mixture while the stirring proceeds. The diisobutenels added ina ratio of one molecular proportion of diisobutene'to two molecular proportions of isobutane, the isobutane being advantageously present in substantial excess of this proportion. It is advisable that the oleflnes should be added gradually to the mixture while the stirring proceeds. The temperature empioyed may ordinaril be about 0 C. In the case of isobutane however the temperature of the reaction is determined by the boiling point of the iso-paraflin which is l0.2 C. It therefore the reaction be carried out under pressure the temperature oi the reaction maybe higher whereby the liquid phase is maintained during the reaction. Stirring oi the mixture is continued for a I short period after all-the olefine has been added, whereupon the mixture is allowed to settle and the lower acid layer withdrawn on settlement. apparently little changed except in respect 0! colour. The clear colourless upper hydrocarbon layer alter settlement is soda-washed and distilled. It is iounlito be almost entirely saturated, the oleflne having apparently completely reacted. Some of the original iso-paraflin is recovered and can be re-processed. When normal parafllns are present in the feed stock they too will be re- 40 covered unchanged. They should preferably be separated from the recovered unchanged isoparaflln before re-processing the latter. The residual material has a pleasant odour and is almost entirely iso-paraiilnic in composition.

In carrying out the reaction advantageously, it is desirable to employ a volume ratio of total hydrocarbon to sulfuric acid initially of between about 1.5:1 and about 2.0:i with a calculated ratio after all or theolefin has been added of between about 2.5:1 and about 4.4:1. These ratios will be apparent from an inspection of the follow. ing examples wherein the volume ratios employed are shown to fall within these ranges. For practical purposes the ratios may be determined by computing upon the basis of volumes oi isoparratio when computed on the amount 01' hydrocarbon to sulfuric acid employed is not strictly accurate at the conclusion of the alkylation reaction since some olefinic reactant remains abmaintained in'the alkylation reaction are more fully set forth and claimed in co-pending divisional application Serial No. 379,442, filed February 18, 1941.

The following are 'a number of examples of the carrying out or the process oi production of a motor iuel according to the invention under a variety of conditions and in the use of various 1 oleflnes and iso-paramns.

EXAMPLE 1' Four hundred cc. of concentrated commercial sulphuric acid (approximately 97 per cent) are charged with 400 grams (about 667 cc.) of liquid isobutane at l2 G. into a vessel fitted with an eiilcient stirrer and surrounded by a bath oi cooling liquid maintained at -10 C. to 12 C. 400 grams (about 533 'cc.) of dilsobutene are slowly run into the mixture over a period 0! two hours and stirring is continued for a further period of 30 minutes after the addition of diisobutene. The volume ratio of total hydrocarban to acid was about 1.67:1 initially and was about 3:1 or somewhat lower after all the diisobutylene had been added. The mixture is allowed to settle and the lower acid layer is run on. The acid layer is straw coloured and has increased in volume by about 15 do. The upper hydrocarbon -layer is soda-washed and distilled. It boils over a comparatively wide range, and

contains a considerable quantity of unreacted isobutane, the fraction Ell-150C. representing 48 per cent of the total hydrocarbon charge. The portion boiling between 90 and 110 C. has an octane number of 95.5 (C. F. R. motor method).

The C. 'F. R. motor method of determinin knock-rating is described in The Principle of Motor Fuel Preparation and Application" by Nash and Howes, vol. 11, paragraph 759.

' Four hundred cc. of concentrated commercial sulphuric acid (approximately 97 per cent) are thoroughly mixed with 600 cc. isopentanein a vessel surrounded by ice and fitted with a stirrer. Four hundred cc. diisobutene are added gradually over a period oftwo hours. The initial volume ratio of total hydrocarbon to acid was about 1.5 1. The final ratio was about 2.521 or actually slightly lower due to the condensation reaction. Stirring is continued for a further period. of 30 minutes after the diisobutene has been added. At the end of this time the mixture is allowed to settle and the lower acid layer is removed. The recovered acid is straw coloured a volume of 415 cc. approximately. The upper layer of treated hydrocarbon is soda-washed and distilled; It

distill over a wide range and contains a propor- I aflins, olefins and sulfuric acid actually employed, although it is realized that the final volumetric tion of isopentane which has not reacted. The

, EXAMPLE 3 Six hundred cc. of isopentane and 400 cc. of

sulphuric acid (approximately 97 per cent) were placed in a vessel cooled in ice and the mixture vigorously stirred. When thoroughl cold 400 cc. of diisobutene were slowly added over a period of 2 hours, after which stirring was continued for a further half hour. The hydrocarbon to acid volume ratios were maintained within the ranges set forth in Example 2. The reaction product was then allowed to settle and the upper colourless hydrocarbon layer withdrawn. The acid which was a pale straw colour increased in volume in the treatment by 5-15 cc., while the volume of the hydrocarbon layer after neutralisation was approximately 875 cc., im specific gravity was .713 at 60 F., and its bromine number (Francis method) 4. The. Francis method of determinin bromine number is described in The Principles of Motor Fuel Preparation and Application by Nash and Howes, vol. II, paragraph 573. After removalby distillation of unchanged isopentane the specific gravity was .731 at 60 F., and 34 per cent boiled between 50 and 200 C. leaving a residue having a specific gravity 012789 at F., and bromine number (Francis) '27. The product was fully saturated and essentially iso-parafilnic in composition. The yield of the hydrocarbon boiiing above 50 C. represented 176 per cent of the olefine taken. The material produced had a high anti-knock rating and was produced without the application of heat and without pressure.

440 grams (about 730 cc.) of isobutane and Q40 I grams (about 587 cc.) of the polymer gasoline. The polymer gasoline was slowly added in a period of 1 /4 hours, the stirring being continued for a further hour. The'recovered acid was rather darker in colour than that recovered in Example No. 3, and had increased involume to 450 cc. The amounts of reactants and acid correspond to an initial hydrocarbon to acid volume ratio of about 1.82:1 and a final ratio of about 3.29:1. The lwdrocarbon layer after the removal of isobutane had a specific gravity of .728 at 60 F., and bromine number (Francis) 31. tionation yielded a product boiling over a wide range, 74 per cent boiling to 200 6., having a specific gravity of .715 at so r-n, bromine nu1n= her (Francis) 21.5 and a residue having a specific gravity of .801 and bromine number (Francis) 57. Th distillate boiling to 200 C. has a pleasant odour and an octane number 84.6 (C. F.

R. motor method).

with an addition of ethyl fluid equivalent .to 2 cc. tetra ethyl lead per tl'mp.) gal. the octane number was raised to 95.5.

It may be noted that while the bromine numcracking plant in which a petroleum stock is sub-' would have resulted in an even lower bromine number of the fractionated product.

EXAMPLE 5 Sixteen hundred cc. of sulphuric acid (9'? per cent) were placed in a pressure vessel provided with a stirrer and an external jacket through which cold or warm kerosene or the equivalent could be circulated, and 1800 grams (about 3210 cc.) of isobutane were added. The acid andparafiln were then stirred with warm kerosene circulating through the jacket, until the temperature of the mixture reached 20 C., the pressure reaching 45 lb. per sq. inch (gauge), when 1800 grams (about 2490 cc.) of diisobutene were slowly jected to a cracking distillation may first be treated in known manner with sulphuric acid (60 per cent) followed by'heating and polymerisation whereby there is produced a mixture of diisobutene and triisobutene in addition to a proportion of unchanged material. The diisobutene and triisobutene may be subject to contact with an iso-paraffln in the presence of sulphuric acid as hereinbefore described.

Alternatively the mixture of diisobutene and triisobutene may be fractionated and the diisobutene may be hydrogenated by known means to produce an isooctane of 100 octane number, and

added with vigorous stirring. Cooled kerosene was circulated through the jacket during this addition. to remove the heat evolved, so maintaining the temperature of the mixture at about 20 C.

The addition required 1% hours, after which stirring was continued for a further /2 hour. The pressure had then fallen to about 10-15 lb. per sq. inch (gauge). The hydrocarbon to acid ratios were initially 2:1 and finally about 3.56:1. To facilitate handling, the product was then cooled down to C., the acid and hydrocarbon tane), 2.3 dimethylbutane, 2.3- and 2.4-dimethylpentane and 2.2.5 trimethylhexane.

TABLE 110. 1

Tabulated examples of treatments carried out according to the invention in which the following oleflnes, viz: (i) diisobutene, (ii) triisobutene and (iii) firopylene were used with isobutane, in each case in the following proportion Sulp uric acid (approximately 97% except in run No. 5 in which the acid strength was 100.6%)

Isobutene Oleflne (i) or (ii) Oletlne (iii) Boiling range of product: 27-185 C. Residue 185 Per cent Run Oleflne, Toexgp" ggg P t Engine test P t N i 09 er can o g l on oleflne 8. G./60 F. 26 011 0165118 (H60:

i taken 50% in Neat tetraethyi taken H. 0. SJ lead per (imp.) gal.

(iii) -30 150 122 1 .698 67.4 82.5 93.3 23.0 2.5 .776

Basic blending material, 52.5 octane number. I

layers separated, and the hydrocarbon layer comm TABLE N0, 2

The results of the pletely neutmhed with .4. s. T. M. (Amencan Standard Test Method) treatment in the use of diisobutene as olefinic material and isobutane as the paraflin are recorded below in run No, 2 of Table No. 1, together with the results of similar runs when using triisobutene under the same conditions (runs 3 and 4 Table Similar resultsare obtained when operating at +30 C. although there is a little more $02 formation than at the .lower temperature. The acid howeverretains the same appearance. I

By operating at 10 C. a somewhat lower yield of useful product, that is a fraction having a boiling range of 27-185 C. is obtained, but this possesses a slightly higher octane rating (runs 1 and 3Table No. 1). The efliciency of the agitation is an important factor, the product improving with increasing efliciency of agitation.

The acid in these runs is not spent and maybe used repeatedly or employed for other refining operations.

Isobutene may be used instead of or together i with diisobutene or triisobutene or other such olefines or mixtures of diisobutene and triisobutane may be used.

distillations of the products of runs 2, 4 and 5 referred to in Table No. 1

Run 2 Run 4 Run 5 Initial boiling point, C 43 32 43. 5 2% 64 44 59. 5 6%; 77. 5 55 69 1 90 so so 102 93. 5 90 30 110 105 96 40 115.5 111 101.5 509 120. 5 122 109 60 129 131 -122 140 .143. 5 145. 4 162 167 189. 5

190. 5 198 200 Final oiling point 257 244 248 Total distillate, percent 98 98 97. 5

Residue l l i 1 l l. 5 3 l0. 5 5. 5 19 25 36. 5 10 07 67 v In run N0. 5 of Table No. 1 the reaction between isobutane and propylene was conducted in the same way as with isobutane and diisobutene. Propylene was added as liquid under pressure and sulphuric acid containing 2.5% free sulphur trioxide (equivalent to 100.6% sulphuric ethyl lead per gallon (Imp.) rose to 100 octane acid) was used. At the end of the reaction the number. Similar results were obtained in the pressure fell practically to that of the atmosuse of triisobutene in place of the dimeride. On phere on cooling the vessel to C. the other hand the use of isobutane in substan- Inasmuch as when using propylene. a small 5 tial or considerable excess offers relatively little amount bfdiallryl sulphate is present in the hydisadvanta e si ce t a be a y e ove ed y drocarbon layer, neutralisation should be thordistillation and re-used. oughly carried out (as for example by stirring By substantial or considerable excess is with per cent soda for 5 hours) to prevent meant asubstantially greater excess of isobutane the formation of free acid and acid products with .10 than that small excess required to ensure against consequent charring of the contents of the still the momentary presence in the vigorously stirred during the subsequent distillation. reaction mixture of a, local excess of the olefine The product from this reaction contains conas it is slowly added and admixed with isobutane siderable quantities of 2.3- and 2.4-dimethylpenor isopentane and sulphurict acid 1(luring the petanes. riod of contact, which subs antia y grea or ex- EXAMPLE 6 .0ess may reach a considerable proportion with In the foregoing examples the proportion of the practcial advantages referred to.

TABLE No. 3

Tobulated results of three experiments carried out according to the invention in which the isobutanezdiisobutene ratios by weight were respectively 1:1, 2:1, and 4:1.

Diisobuteno and isobutuno at 0. using 96.9 per cent acid. Pressure used sufiicient to maintain the isobutsne in the liquid phase. Time of addition: 90 min. Time of stirring: min. Ezpt. No. 1.l:1 3000 cc. isobntanc Ezpt. No. 2.2:1 4500 cc. isobutane Ezpt. No. 3.4:1 6000 cc. isobutone 1800 g..diisobutene 1350 g. diisobutene 900 g. diisobutene Product 27 C. Product 27185 C. Residue E A. s. T. M. distillation Engine test g a i I H k 3 it as e a a a e s e s a a a 5. 5. d m is e z z 6. s it the isoparafiin to olefine is approximately such 1 EXAMPLE 7 that for each molecule of the former one molecule of the latter or its equivalent in the case of polymerides is taken. Since the polymerides To 3000 cc. isobutane and 1600 cc. of sulphuric acid (9'7 per cent) were added while maintaining 45 the temperature at 20 C., 2250*cc. of liquid bu- :3f1:fif ififi ffg bfioi l fif 3 13 353 bane-2 during e 1.1/2 0 W eumcieni tity of iso-parafiln required is determined by the pressure.wa apphed to a t hquld phase monomeric equivalent. of the polymer, e. g'. two After agltatmg for further 1/2 the Product molecular proportions of iso-butane to one of was worked up 3 m prevlous diisobutene, three molecular proportions of'isoamplgs The mma'l volume p of hydmcarbqn butane to one of trfisobutene and so OIL The to acid was about 1.87:1, while the final ratio proportions indicated in the foregoing examples was about 3.28.1. The overall yield of product are not however essential; on the contrary based upon the olefine taken was 160 per cent,

the specific gravity of the product .706 at 60 F. stantial or considerable excess of the iso-paraflin or ismparamns is generally advantageous in and the bromine number (Francis) 3. On d1st1llation the yield of the fraction having the boiling point of overall y1eld of the product, high proportion of useful material in the product and the range was equivalent F per cent lower boiling range of the small residue obtained. the olqfine taken Thlos fractmn These advantages were demonstrated in the reclfic gljavlty of at bromme t suits recorded in the following Table No. 3 which 60 (Francls) less than 5 and i octane mtmg of were obtained with dfisobutene and isobutane in 90.2, octane number increasing to 100.3 octane the weight ratios of I, and 1A The rep number on addition of ethyl fluid equivalent to sults recorded in rlrable N0. 3 a subc0. Petra lead per 21111011 (11111).) .The stantial or considerable excess of iso-butane dlstmatlon range of theproduct was glbstantlany favours the formation of the octane fraction the Same Wh obtalwd when dnsobutene 1s whibh in the third experiment reccrdedwas lama used under simllar conditions. Fractionation in- The proportion of useful product is much higher dicated the presence of appreciable quantities than when equimdlecmar proportions of is0bu I of iso-octane (2.2.4 tr1methylpentane) in this tone and olefine are used. -The yield of 2.2.4 triproduct" methylpentane recoverable by distillation is also EXAMPLE 8 increased considerably. An engine test on the The olefine employed consisted in a fraction total productfrom that experiment after rehaving a boiling range of 105-112 C. taken from moval only of excess iso-butane gave an octane the product formed by the condensation of nrating of 90.6 octane number, and with an addibutene and isobutene in the C4 cut from gas detion of ethyl fluid equivalent to 1.5 cc. of tetra rived from an oil cracking plant, when using a ,2,ses,soo'

phosphoric acid catalyst. The material in question consisted largely of the condensation productfrom one molecule each of n-butene and isobutene, being essentiallya 2.2.3, trimethylpentene, and is hereinafter referred to as butene-isobutene polymer.

To a mixture of 1600 cc. sulphuric acid (97 per cent) and 3000 cc. of isobutane were added 1800 g. (about 2430 cc.) of butene-isobutene polymer over a period of 90 minutes maintaining the temperature steady at 20. C. against the heat of Y condensation, the pressure being sufllcient to maintain the liquid phase. Finally, after a further 30 minutes agitation, the product was sepa rated from the acid and'worked up as in previous examples. The initial hydrocarbon to acid ratio was about 1.87:1 with a final ratio of about 3.421;

The yield of the crude product of specific gravity .713 at 60 F., and bromine number (Francis) 2, was equivalent to 158 per cent yield based upon the olefine taken. On distillation the yield of the fraction having a boiling range of 27-185" C. was

equivalent to 135% of the olefine taken. This fraction had a specific gravity .707 at 60 F.,

bromine number (Francis) less than 1 and an octane rating of- 87, the octane number increasing to 97.9 with addition of ethyl fluid equivalent I to 1.5 cc. tetra ethyl lead pergallon (Imp.).

The product obtained from a crude buteneisobutene polymer, a fraction of boiling range 95-120 C. which also contained a small amount of diisobutene gave practically the same yield, but the octane rating of the product was 80.7 octane. number, and 99.2 octane number with addition of 1.5 cc. tetra ethyl leadper gallon (Imp) EXAMPLE 9 To 2000 cc. isobutane and 1070 cc. of sulphuric acid (97 per cent) were added while maintaining the temperature at 20 C. and stirring vigorously, 2700 cc. of a crude C4 fraction cut from cracking gas and containing 94% of C4 unsaturated hymaintainthe reactantsin the liquid phase. Ad-

I comprising alkylating an isoparafiin with an olefin reactant comprising essentially a reactive.

to formiso-octanes.

4. A process for the production of iso -octane, which-comprises reacting di-isobutylene with isobutane in the presence of sulphuric acid to form iso-octane.

5. A process for the manufacture of iso-octanes, which'comprises subjecting a hydrocarbon fraction containing isobutylene and isomeric normal butenes to cross polymerization in the presence of. a selective polymerization-catalyst .wher'eby mixed di-isobutylenes are formed and alkylating lower boiling polymer of isobutene in the presence of sulfuric acid of high concentrationat a temperature between about 10 C. and about +30 C. while vigorously stirring the reaction mixture duringthe period of contact, contacting the reaction mixture under alkylation reaction conditions for sufficient period of tume to effect the substantial production of saturated isoparafiinic hydrocarbons, allowing the reacted mixture to settle, separating normally liquid isoparafiinic hydrocarbons from the supernatant layer and recovering the desired product from this layer.

' drocarbons; the pressure used being sumcient to dition was carried out over a period of 90 minute's followed by a further 30 minutes agitation.) The initial hydrocarbon to acid volume ratio was about 1.87:1 with the. final ratio being about 4.421. The crude product after a thorough hen.-

ity of HOB/60 F. and bromine number (Francis) of 1'. Tested on the engine the neat product gave by the C. F. R. motor method 91.6 octane tralisation with caustic'soda was redistilled and yielded a fraction boiling 27-185 C. with a grav-- 8. A process for, the production of a. motor fuel comprising alkylating an isoparaflin with an olefin reactant comprising essentially a reactive lower boiling polymer of C4 olefin in the presence of sulfuric acid of high concentration at a temperature between about -10 C. and about +30 C. wherein the olefin reactant is slowly run into a preformed admixture containing the isoparafiin and sulfuric acid with vigorous agitation, and

maintaining the reaction mixture under alkylation reaction conditions for sufiicient length of time to effect the production of substantial amounts of normally liquid isoparafiin hydrocarnumber rising to 99.5 octane number with the addition of ethyl fluid corresponding to 1.5 cc.

tetraethyl lead per (Imp.) gal.

It will be understood that the process may be advantageously carried out continuously, "and that instead of sulphuricacid being used phosphoric acid may be used alone or with sulphuric acidintheprocess.

' .We claim:

1. A process for the production of highanti knock motor fuel hydrocarbons, which comprises polymerizing isomeric butylenes to di-butylenes and then reacting the di-butylenes with iso-butane to form octanes.

2. A process for the production of iso-octane which comprises polymerizing iso-butylen'ev to di isobutylene' and then reacting the di-isobutylen with iso-butane to form i'so-octane.

3. A process for the production of iso-octanes,

which comprises reacting isomeric di-butylenes.

bone, allowing the reaction mixture to settle, sep- "arating the alkylate products from the supernatant layer and recovering the desired products therefrom.

9. A process as in'claim 7 wherein at least sufficient superatmospheric pressure is employed to maintain liquid phase operation.

10. A process as in claim 8 wherein at least suf-.

ficient superatmospheric pressure .is employed to maintain liquid phase operation.

11. A process for the manufacture of normally liquid hydrocarbons boiling within the gasoline boiling range which comprises reacting low boiling polymers resulting from the polymerization of C4 olefins with an isoparamn selected from the group consisting of isobutane and lsopentane in the presence of concentrated sulfuric acid cata alyst under alkylation reaction conditions.

' 12.' A process for the production of branched chain, parafilnichydrocarbons boiling within the motor fuel range which comprises reacting normally liquid olefinic polymers of normally Easeous olefine with at least one iso-paraflin in the with iso-butane inthe presence of sulphuric acid presence of concentratedsulfuric acid of alkylating strength at a temperature of between about -l0 C. and about +30" C. for sufflcient length of time to effect substantial alkylation of the isoparaii'inic component-with the polymeric component and recovering from the reacted mixture normally liquid, branched chain parafiinic hydrocarbons boiling within the motor fuel range. 1

13. A process as in claim 12 wherein the reaction'is carried out continuously, in liquid phase and with intensive agitation of the reaction mixture.

14. A process as in claim 12 wherein the reaction is carried out in the liquid phase with intensive agitation and wherein the isoparaflinic constituents comprising. essentially, branched chain saturated hydrocarbohs boiling within the motor fuel range which comprises reacting a normally liquid polymer of a normally gaseous monoolefln with at least one isoparafiin in the presence of concentrated sulfuric acid of alkylating strength under alkylation reaction conditions.

aaeasoo 18. A process as in claim 1! wherein the reaction is carried out under at least sumcient superatmospheric pressure to maintain liquid phase operation and wherein the reaction mirtture is vigorously agitated.

19. A process as in claim 17 wherein the olefin is added gradually with agitation in a liquid phase operation to a preadmixture of isoparaflin and sulfuric acid maintained at an initial volume ratio of between about 1.5 1 and about 2.0 1.

20. A process as in claim 17 wherein the olefin is added gradually with agitation in a liquid phase operation to a preadmixture of isoparaifin and sulfuric acid maintained at an initial volume ratio of between about 15:1 and about 2:1 prior to the addition of olefin and wherein the olefin is added in sumcient quantity to give a final total hydrocarbon to acid ratio computed on a basis of original volumes of isoparafiin and acid of between about 2.5: 1 and about 441:1.

21. A process as in claim 17 wherein the olefin is added gradually with agitation in aliquid phase operation to a preadmixture of isoparaflin and sulfuric acid maintained at an initial volume ratio of between about 15:1 and about 2:1 prior to the addition of olefin and wherein the olefin is added in sufficient quantity to give a final total hydrocarbon to acid ratio computed on a basis of original volumes of isoparamn and acid of between about 2.5:1 and about 4.4:1 and wherein the sulfuric acid has a concentration of be= tween about 97% and about 100%.

. ALBERT ERNEST DUNSTAN.

STANLEY FRANCIS BIRCH. 

